Mos Espa is one of few port cities on Tatooine, born out of the desert and built piece by piece over many years. Domed buildings protect the citizens against the glare of the twin suns and the scorching heat. Among the dwellings, workspaces, and commercial operations of many bizarre kinds there are also entertainment areas, including some of colossal scale. The famed Mos Espa Grand Arena can can hold an audience almost as large as the city's entire population.

Most of Mos Espa's inhabitants are settlers and subsistence earners who scratch out a meager living as best they can. The only real wealth in Mos Espa is tied up in gambling and off-world trade, especially in the lucrative black market beyond the trade laws and controls of the galactic government.

In the time of the Republic, slavery persisted in Mos Espa, though the despicable trade was outlawed elsewhere. An entire section of the city's outskirts had been transformed into a Slave Quarter. Live slaves functioned more as prestige possessions than cheap laborers, and owners parted with them only reluctantly. Slaves could even find themselves used as capital in business transactions. The true powers in control of Mos Espa were the Hutt gangsters, who found slavery a useful institution for their purposes, and Tatooine's remoteness allowed them to practice their illegal ventures.